Focus on Backlog and Quality metrics (Neil)

Invalid - Enhancement does not fit with the scope of the project or is already implemented.

helpwanted keyword - This is a valid request, but due to committer resources and other priorities, outside help will be needed to make this happen.

Future - I would use this in conjunction with the helpwanted keyword. I use this for legitimate requests that are important but will not make any planned release, but likely will make a future release.